rustdoc: add GUI test case for docblock table colors

src/librustdoc/html/static/css/rustdoc.css

@@ -639,7 +639,7 @@ pre, .rustdoc.source .example-wrap {
 	border: 1px solid var(--border-color);
 }
 
-.docblock table tr:nth-child(2n) {
+.docblock table tbody tr:nth-child(2n) {
 	background: var(--table-alt-row-background-color);
 }
 

src/test/rustdoc-gui/docblock-table.goml

@@ -2,3 +2,50 @@ goto: "file://" + |DOC_PATH| + "/test_docs/doc_block_table/struct.DocBlockTable.
 
 compare-elements-css: (".impl-items .docblock table th", ".top-doc .docblock table th", ["border"])
 compare-elements-css: (".impl-items .docblock table td", ".top-doc .docblock table td", ["border"])
+
+define-function: (
+    "check-colors",
+    (theme, border_color, zebra_stripe_color),
+    [
+        ("local-storage", {"rustdoc-use-system-theme": "false", "rustdoc-theme": |theme|}),
+        ("reload"),
+        ("assert-css", (".top-doc .docblock table tbody tr:nth-child(1)", {
+            "background-color": "rgba(0, 0, 0, 0)",
+        })),
+        ("assert-css", (".top-doc .docblock table tbody tr:nth-child(2)", {
+            "background-color": |zebra_stripe_color|,
+        })),
+        ("assert-css", (".top-doc .docblock table tbody tr:nth-child(3)", {
+            "background-color": "rgba(0, 0, 0, 0)",
+        })),
+        ("assert-css", (".top-doc .docblock table tbody tr:nth-child(4)", {
+            "background-color": |zebra_stripe_color|,
+        })),
+        ("assert-css", (".top-doc .docblock table td", {
+            "border-style": "solid",
+            "border-width": "1px",
+            "border-color": |border_color|,
+        })),
+        ("assert-css", (".top-doc .docblock table th", {
+            "border-style": "solid",
+            "border-width": "1px",
+            "border-color": |border_color|,
+        })),
+    ]
+)
+
+call-function: ("check-colors", {
+    "theme": "dark",
+    "border_color": "rgb(224, 224, 224)",
+    "zebra_stripe_color": "rgb(42, 42, 42)",
+})
+call-function: ("check-colors", {
+    "theme": "ayu",
+    "border_color": "rgb(92, 103, 115)",
+    "zebra_stripe_color": "rgb(25, 31, 38)",
+})
+call-function: ("check-colors", {
+    "theme": "light",
+    "border_color": "rgb(224, 224, 224)",
+    "zebra_stripe_color": "rgb(245, 245, 245)",
+})

src/test/rustdoc-gui/src/test_docs/lib.rs

@@ -343,6 +343,9 @@ pub trait DocBlockTableTrait {
     /// | header1                  | header2                  |
     /// |--------------------------|--------------------------|
     /// | Lorem Ipsum, Lorem Ipsum | Lorem Ipsum, Lorem Ipsum |
+    /// | Lorem Ipsum, Lorem Ipsum | Lorem Ipsum, Lorem Ipsum |
+    /// | Lorem Ipsum, Lorem Ipsum | Lorem Ipsum, Lorem Ipsum |
+    /// | Lorem Ipsum, Lorem Ipsum | Lorem Ipsum, Lorem Ipsum |
     pub struct DocBlockTable {}
 
     impl DocBlockTableTrait for DocBlockTable {